Structure of Latex-Silica Nanocomposite Films: A Small Angle Neutron Scattering Study

Julian Oberdisse (1) , Bruno Demé (2)

1 LLB - UMR 12 - Laboratoire Léon Brillouin
2 ILL - Institut Laue-Langevin

We report on the synthesis and structure of silica filled latex films. The main stage of the synthesis consists in physico-chemical manipulations of colloidal solutions of nanosilica and nanolatex beads, followed by drying and filmification. Hence, no mechanical energy which might contribute to building or destruction of aggregates of silica beads is supplied to the samples. We have analyzed the structure of the resulting filled latex films by means of Small Angle Neutron Scattering. The scattered intensity varies enormously with the physico-chemical parameters, indicating considerable structural modifications. To rationalize these results, we present a unified description of the data which successfully accounts for the main characteristics of the scattered intensity: the form factor of beads at large q vectors, the position of the intra- and inter-aggregate structure factor peaks, the small-q upturn observed in some cases, and the overall intensity in absolute units. This allows us to quantify the degree of aggregation of the silica in the matrix. It is found that the latter can be varied in a systematic manner by changing pH, silica volume fraction and quantity of added salt. In one extreme case, e.g., the aggregation number changes by a factor of about 1000 at constant silica volume fraction.

Mots clés: polymer; colloid; reinforcement; composite; small angle neutron scattering

Domaines: Matière Molle [cond-mat.soft]

Julian Oberdisse, Bruno Demé. Structure of Latex-Silica Nanocomposite Films: A Small Angle Neutron Scattering Study. Macromolecules, 2002, 35, pp.4397. ⟨hal-00003641⟩